Add comprehensive test suite for game mechanics and level handling

- Introduced `test_final_level_flow.py` to validate final level transitions and game end scenarios.
- Created `test_game_over_flow.py` to ensure game over conditions trigger correctly based on rat counts.
- Implemented `test_keybindings.py` to verify keybinding configurations and their context-specific actions.
- Developed `test_level_editor.py` to assess level editor functionalities and layout computations.
- Added `test_level_io.py` for testing level data serialization and deserialization.
- Established `test_loop_logic_parity.py` to ensure consistent game state across multiple simulation runs.
- Created `test_non_regression.py` to simulate game behavior and capture states for future verification.
- Implemented `test_verify.py` to compare current game states against a golden master for regression detection.

tests/test_keybindings.py

@@ -0,0 +1,159 @@
+#!/usr/bin/env python3
+
+import unittest
+from pathlib import Path
+from unittest.mock import MagicMock
+
+from engine import controls
+
+
+class DummyBindings(controls.KeyBindings):
+    def __init__(self, game=None):
+        if game is None:
+            game = MagicMock()
+            game.menu_up = lambda: None
+            game.menu_down = lambda: None
+            game.menu_left = lambda: None
+            game.menu_right = lambda: None
+            game.reset_game = lambda: None
+        super().__init__(game)
+
+    def spawn_rat(self):
+        pass
+
+    def toggle_audio(self):
+        pass
+
+    def toggle_full_screen(self):
+        pass
+
+    def start_scrolling(self, direction):
+        pass
+
+    def stop_scrolling(self):
+        pass
+
+    def spawn_new_bomb(self):
+        pass
+
+    def spawn_new_nuclear_bomb(self):
+        pass
+
+    def spawn_new_mine(self):
+        pass
+
+    def spawn_new_gas(self):
+        pass
+
+    def spawn_gas(self, parent_id=None):
+        pass
+
+    def toggle_pause(self):
+        pass
+
+    def reset_game(self):
+        pass
+
+    def quit_game(self):
+        pass
+
+    def menu_up(self):
+        pass
+
+    def menu_down(self):
+        pass
+
+    def menu_left(self):
+        pass
+
+    def menu_right(self):
+        pass
+
+
+class KeybindingProfileTests(unittest.TestCase):
+    def test_shipped_profiles_expose_all_weapon_actions(self):
+        dummy = DummyBindings()
+        conf_dir = Path(__file__).resolve().parent / "conf"
+        weapon_actions = {
+            "spawn_new_bomb",
+            "spawn_new_nuclear_bomb",
+            "spawn_new_mine",
+            "spawn_new_gas",
+        }
+
+        for config_path in sorted(conf_dir.glob("keybindings*.json")) + sorted(conf_dir.glob("keybindings*.yaml")):
+            bindings = controls._load_bindings_from_file(config_path)
+            validated = dummy._validate_bindings(bindings, config_path)
+            game_bindings = validated.get("keybinding_game", {})
+            self.assertTrue(game_bindings, f"missing keybinding_game in {config_path.name}")
+
+            actions = set(game_bindings.values())
+            self.assertTrue(
+                weapon_actions.issubset(actions),
+                f"incomplete weapon bindings in {config_path.name}: {sorted(actions)}",
+            )
+
+    def test_shipped_profiles_define_level_dialog_bindings(self):
+        dummy = DummyBindings()
+        conf_dir = Path(__file__).resolve().parent / "conf"
+        required_sections = {
+            "keybinding_start_menu", # Corrected from level_intro since we removed it
+            "keybinding_level_clear",
+            "keybinding_defeat",
+            "keybinding_run_complete",
+        }
+
+        for config_path in sorted(conf_dir.glob("keybindings*.json")) + sorted(conf_dir.glob("keybindings*.yaml")):
+            bindings = controls._load_bindings_from_file(config_path)
+            validated = dummy._validate_bindings(bindings, config_path)
+
+            for section_name in required_sections:
+                section = validated.get(section_name, {})
+                self.assertTrue(section, f"missing {section_name} in {config_path.name}")
+                values = set(section.values())
+                self.assertIn("reset_game", values, f"missing confirm binding in {section_name} for {config_path.name}")
+                self.assertIn("quit_game", values, f"missing quit binding in {section_name} for {config_path.name}")
+
+    def test_trigger_uses_start_menu_context(self):
+        game = MagicMock()
+        dummy = DummyBindings(game)
+        calls = []
+        
+        # Override action_dispatcher for testing
+        dummy.action_dispatcher["reset_game"] = lambda: calls.append("reset")
+        dummy.action_dispatcher["quit_game"] = lambda: calls.append("quit")
+        
+        dummy.bindings = {
+            "keybinding_start_menu": {"keydown_Return": "reset_game"},
+        }
+        game.game_status = "start_menu"
+        game.menu_screen = "start"
+        game.game_end = (False, None)
+
+        dummy.trigger("keydown_Return")
+
+        self.assertEqual(calls, ["reset"])
+
+    def test_trigger_uses_level_clear_context(self):
+        game = MagicMock()
+        dummy = DummyBindings(game)
+        calls = []
+        
+        dummy.action_dispatcher["reset_game"] = lambda: calls.append("reset")
+        dummy.action_dispatcher["quit_game"] = lambda: calls.append("quit")
+        
+        dummy.bindings = {
+            "keybinding_level_clear": {"keydown_Return": "reset_game"},
+            "keybinding_paused": {"keydown_Return": "quit_game"},
+        }
+        game.game_status = "paused"
+        game.menu_screen = None
+        game.game_end = (True, "level_clear")
+
+        dummy.trigger("keydown_Return")
+
+        self.assertEqual(calls, ["reset"])
+
+
+if __name__ == "__main__":
+    unittest.main()